Generally, in the case of application software such as game software or the like that operates in user computers such as (for example) personal computers, portable information terminals or the like, a plurality of different versions are prepared according to various types of software execution environments such the OS (operating system), language use, hardware construction and the like, or according to whether or not there is any software cost, payment of a fee or the like.
For example, even in the case of the same software, different versions may be prepared according to the language that is used, e.g., as in an English language edition, Japanese language addition, Chinese language edition or the like. Furthermore, it is fairly common for a version that is provided free of cost and a version that is provided for a fee to be prepared, and for the user to be induced to upgrade from the free software to the software that is provided for a fee. Such free software is also called a “test edition” or “trial edition”, and the software that is provided for a fee is called the “product edition” or “complete edition”. Compared to software of the same type that is provided for a fee, free software usually shows a partial limitation of the functions or a restriction on the trial use period or number of times of trial use permitted. Users who recognize the value of the software as a result of such trial use of free software accomplish upgrading of the software version by purchasing the software that is provided for a fee from a web site that provides this software, and downloading the purchased software, or by purchasing packaged software for a fee at a retail outlet.
Meanwhile, since software is digital data and can easily be copied, and since such software is characterized by the fact that such copying causes almost no deterioration in the software, illegal copying and unauthorized use are major problems. Accordingly, it has conventionally been the practice to discriminate by means of user verification or the like between regular users who have purchased the software (software license) and illegal users who have not obtained such a license, and to take steps so that only regular users are allowed to use the software.
For instance, a technique is known in which a product ID that is printed on the software package or recording medium is input when the software is installed, and it is thus ascertained whether or not this software is a regularly purchased product (e.g., see Japanese Patent Application Laid-Open No. 2002-258963, paragraph 0003).
Furthermore, a technique is also known in which key data that is required in order to use the software is requested from a license management server installed on the internet, and the system is devised so that in cases where the user is confirmed as a regular user by user verification, the user can acquire this key data from the license management server, and can start and use the software by means of this key data (e.g., Japanese Patent Application Laid-Open No. 2002-6972, Japanese Patent Application Laid-Open No. 2002-297254).
Conventional techniques that discriminate whether or not a user is a regular user by inputting a product ID (product key) are protective mechanisms that merely input an ID consisting of simple characters or symbols at the time of installation, and are therefore easily circumvented. Accordingly, software that has only a protective mechanism (copyright protection mechanism) of this type cannot in fact exclude illegal copying and unauthorized use.
A technique in which user verification is performed with a license management server, and key data is transmitted to the user computer to start the software in case where a normal verification is made, shows an improved protective power compared to a technique in which a product ID is simply input. However, the software is already placed in a state that allows starting in the user computer, and the user must wait to acquire the key data. Accordingly, if the software that is in a key data waiting state is illegally copied, and the key data is obtained by some other method, the protective mechanism can be circumvented, and the software can be used.
Meanwhile, in recent years, as the processing capacity of computers has increased and communications networks have achieved higher speeds, methods have been proposed for executing desired software at the time desired by users. The streaming system and the downloading system are known as distribution systems that are suitable for such on-demand distribution of software.
In the case of the streaming system, the user computer simultaneously performs playback while receiving software from a server. Then, data that is unnecessary is immediately discarded after this playback is completed. Accordingly, in the streaming system, since no data remains at the point in time at which the inspection by the user is completed, the software cannot be illegally copied without using some special type of software or the like. However, in the case of the streaming system, the software data must be transmitted each time that the user desires to inspect the software; accordingly, even in cases where a broad-area, high-speed communications network is provided, the traffic on the communications network is increased, and the burden on the server is also increased, if numerous users desire streaming distribution at the same time.
In the case of the downloading system, on the other hand, software that is desired by a user is downloaded from a server and accumulated in the user computer, and this software is executed in the user computer; accordingly, the time for which the data is flowing through the communications network is short, and distribution requests from numerous users can be handled. In the case of the downloading system, however, software remains as downloaded in the user computer; accordingly, illegal copying and the like can be performed more easily than in the case of the streaming system.
Furthermore, for example, it is a widespread practice for game programs and the like to be placed in circulation in a form in which these programs are fixed on various types of recording media such as CD-ROMs, DVD-ROMs, hard disks, semiconductor memories and the like. In such cases as well, game programs and the like are improperly copied, protective mechanisms are improperly destroyed, and the programs are improperly used, as was described above.